The present invention relates to a stapler for applying staples to sheets of paper discharged to the sorter or finisher inside an image forming device such as a photocopier or printer.
FIG. 1 shows a cartridge used in a stapler of the prior art. The staples 1 used to staple documents are stored in a continuous sheet of staples (a). In other words, the staples 1 are fused together in a consecutive sheet of staples (a). The staples 1 are driven one by one into documents, where they are bent into an angular C-shape and severed from the sheet of staples (a). The sheet of staples (a) is wound in a roll and housed inside a cartridge 100. The cartridge 100 is equipped with a housing unit 101 for housing the rolled sheet of staples (a) and a guide unit 102 for guiding the end of the rolled sheet of staples (a) out from the cartridge 100. The housing unit 101 has an outer diameter that conforms to the rolled sheet of staples (a) and a round inner periphery.
Also, the guide 102 for guiding the sheet of staples (a) is equipped with a pair of walls 102a, 102a held apart at a given interval, and a protrusion 102b moving horizontally between the walls 102a, 102a. 
The protrusion 102b has a reverse motion stopping tab 12. The reverse motion stopping tab 12 has a tip that makes contact with the sheet of staples (a) drawn out from the guide unit 102. This accommodates the sheet of staples (a) moving in the direction of the arrow in FIG. 1, but prevents the sheet of staples (a) from moving in reverse.
Guide tabs 102c are located in the inner surface of the walls 102a, 102a, and these guide tabs 102c prevent the sheet of staples (a) from rising off the base 102h of the guide unit 102.
The walls 102a, 102a are also equipped with tip contacting units 103, 103 for making contact with the main body of the device when the cartridge 100 is in the main body of the device. A catch 102g is situated on the base 102h of the guide unit 102 for keeping the cartridge 100 in a certain position inside the main body of the device.
In the stapler with a cartridge 100 installed, a staple 1 is driven through a stack of paper cleanly and the staple 1 is bent after the staple 1 has been applied to the stack of paper. If the stapling process does not proceed smoothly, the staple becomes jammed.
When a staple 1 becomes jammed, the staple 1 remains inside the main body of the device. If the jammed staple 1 remains inside the device, the stapling operation cannot be performed until the jammed staple is removed.
When a staple becomes jammed, the cartridge is detached from the stapler and the jammed staple 1 is removed. When the jammed staple 1 is removed, a finger is inserted under the jammed staple 1 to remove the jammed staple 1 from the sheet of staples (a).
If the jammed staple cannot be pulled away, the sheet of staples (a) has to be pulled out to an unjammed section. However, it is difficult to return the extended sheet of staples (a) to its original position. If the cartridge has a reverse motion stopping tab, then it is impossible to return the extended sheet of staples (a) to its original position.
Because the extended sheet of staples (a) cannot be returned to its original position, the extended portion has to be cut off. This results in a waste of staples.
When a jammed staple is removed from the sheet of staples (a), the unjammed staples are bent. Even slightly bent staples cannot be applied smoothly to stacks of paper. The result is even more jammed staples.
When a jammed staple is removed from the sheet of staples (a), the unjammed staples also become slightly separated. As a result of this slight separation, a blank may be fired during the stapling process.
Therefore, there remains a need for a stapler in which only jammed staples are consistently removed.
The embodiment of the present invention relates to a stapler having a housing unit for housing a sheet of staples, a cartridge forming a guide unit for supporting the sheet of staples drawn from the housing unit, and a main body for accommodating the cartridge. The main body of the device is equipped with a driver mechanism for detaching a staple from the sheet of staples and driving the detached staple through a stack of paper and a sheath bracket for guiding the driver mechanism in the direction of the driving motion. A stopper restricts the position of the end of the sheet of staples, and release holes are situated in a position corresponding to the end of the sheet of staples restricted by the stopper so the staple driven by the driver mechanism passes through in the driving direction.
In another embodiment, the stopper is situated on the tip of the guide unit for the cartridge, and the cartridge can be detached from the main body of the device.
In yet another embodiment, the stopper is situated on the sheath bracket of the main body of the device, an opening is formed in the sheath bracket, and the release holes are exposed by the opening.
In another embodiment, the stopper is situated on the driver mechanism of the main body of the device, an opening is formed in the sheath bracket used to guide the driver mechanism, a cover is formed to cover the opening, and the release holes are exposed when the cover is opened and closed.
In another embodiment the release holes are at least the size of a width of a single staple.